TMP390 Resistor Programmable Temperature Switch is a Ultra small, Dual Channel Resistor Programmable Temperature Switch that enables Protection and Detection of System thermal Events from -50°C to 130°C.
IC TMP390 Offers Independent Over Temperature (hot) and Under Temperature (cold) detection. As per the TMP390 Datasheet – The trip temperatures (TTRIP) and thermal hysteresis (THYST) options are programmed by two E96-series resistors (1% tolerance) on the SETA and SETB pins. Channel A resistors can range from 1.05 KΩ to 909 KΩ, representing one of 48 unique values. Channel B resistors can range from 10.5 KΩ to 909 KΩ.
Functional Circuit Diagram
The TMP390 requires two resistors to set the two trip points and hysteresis, according to Threshold and Hysteresis Setting, the hot and cold channel device. The output of the TMP390 is open-drain and requires two pullup
resistors. Texas Instruments recommends to use a pullup voltage supply that does not exceed VDD + 0.3 V. The pullup resistors used in between the OUTA and OUTB pins and the pullup supply should be greater than 1 kΩ. The device powers on when the supply voltage goes beyond 1.5 V, and starts sampling the input resistors to set the two trip points and hysteresis value after power-on.
These values will remain the same until the device goes through a power cycle. After the device sets the trip points and hysteresis level, the device will update the output every half a second. The conversion time is typically 0.65 ms when the temperature is checked against the trip points and the outputs are updated. The device remains in standby mode between conversions. If either channel is not used, the output can be grounded or left floating. – Information as appears in the Datasheet of TMP390.
Features of TMP390
Some of Notable Features of IC TMP390 listed here.
- Operating voltage of this IC is 1.62V to 5.5V
- Open Drain output
- Resistor programmable temperature trip points and hysteresis options
- Separate outputs for overtemperature or under temperature detection
- Measurement Range from −55°C to +130°C
- Ultra-low power consumption: 0.5 µA typical at 25°C
- Available in a SOT-563 (1.60-mm × 1.20-mm), 6-pin package